Foam generating devices



Jan. 10, 1961 H. G. STROHM 2,967,698

FOAM GENERATING DEVICES Filed March 31, 1958 1 nvenior H a rold G. Strohm Attorney Unite States Patent 2,967,698 FOAM GENERATING nnvrcns Harold G. Strohm, Waukegan, Ill., assignor to Production Specialists, West Allis, Wis., a partnership of Wiscousin Filed Mar. 31, 1958, Ser. No. 725,288

2 Claims. (Cl. 261-76) This invention relates generally to foam generat'ng devices, and while not limited thereto, relates more particularly to devices for generating foam for use as a coolant in metal machining processes.

Intense heat generated by friction in metal machining requires that commercial coolant, various types of oil, or otherliquids be employed to proong tool life and to prevent damage to the material being worked. Former y, a mist, a continuous flood or a solid stream of coolant was directed onto the tool and the material. It has been discovered, however, that use of coolants in a foamy state produces more satisfactory results in that splashing is substantially eliminated, additional surface area of tool and material is covered by the foam whch tends to cling, and more etficient coding is efie-ted s'nce a larger quantity of coolant can be app ied and is retained for a given period. Some exist ng types of foam gene ating devices have proven unsatisfactory because they are relatively complicated in construction, employ scre'ns or a number of moving parts, a e extremely susceptible to clogging with metal chips and other foreign mat'er, or require the use of compressed air or other gases in conjunction with a liquid coolant to achieve foaming action. It is desirable, therefore, to have a foam generating device which overcomes the aforementioned and other difficulties and has numerous other advantages.

Accordingly, it is an object of this invention to pro'ide an improved foam generating device for liquid coo'ants which does not employ screens, moving parts, or czmpressed gases to obtain foaming action.

Another object is to provide a device of the aforesaid character which is relatively simple to construct, employs a minimum number of constituent elements, is extremely reliable in use, can be readily cleaned, can be economically produced, is durable, and is readily adaptable to a wide variety of applications.

Other objects and advantages of the invention will hereinafter become apparent.

The accompanying drawing illustrates one embodiment of the invention which will hereinafter be desc ibed, it being understood that the embodiment i'lustrated is Sll3- ceptible of various modifications with respect to det ils thereof without departing from the scope of the appended claims.

In the drawing:

Figure l is a cross sectional view, actual size, of a f am generating device embodying the invention taken along line 1-l of Fig. 2;

Fig. 2 is a top p'an view of the device showing cer'ain details thereof; and

Fig. 3 is an elevational view in reduced scale of the device shown in Figs. 1 and 2 ilustrating the man er in which it is employed with appropriate inlet and outlet piping.

Referring generally to Figs. 1, 2 and 3, the reference numeral designates a foam generating device incorporating the invention. The foam generating device 10 comprises a generally cylindrical hollow shell member 11 materias may be utilized instead.

Referring specifically to Fig. 1, itis seen that the bot om wall 12 of shell .11 is provided with an integrally formed substantially cylindrical hollow stem portion 14 which extends upwardly for some distance into the chamber 15 of the shell. The wall of the stem 14 is arranged wfth respect to the wall of the'shell 11 so as to form a moat 16 therebetween. Stem portion 14 is provided with a bore 17 which communicates with chamber 15 and the bore is threaded and adapted to accommodate the externally threaded end of a discharge pipe or nozz'e 25, as Fig. 3 makes clear.

Referring to Figs. 1 and 2, it is seen thatcover member 13, which has a substantially circular peripheral cont ur, is provided with an annular groove or shoulder 18 around its lower outer edge which adapts it to fit snugly within the open upper end of shell 11.

Three rivets or pins 19a, 19b and exend through the wall of shell 11 and into the cover to rigidly secure the latter to the shell.

Cover member 13 has a central po tion 20 wh'ch is substantia'ly thickerthan the remainder thereof and which depends into chamber 15. A rel"tively large thraded 'rec' ess or opening 21 extends into but not through portion '20 and is adapted to accommodate the externally threaded end of an inlet pipe 22, as F g 3 make clear. The bottom wall or floor 23 of port on 20 is provided with four orifices 23a, 23b, 23c and 230. which extend therethrough and communicate with chamber 15. Preferabl' the orifices 23a, 23b, 23c and 23d are arranged in a c rclc about the center point of floor 23 of portion 20 and are spaced an angular distance of ninety degrees from each other, as Fig. 2 makes clear. Each orifices 23a, 23b, 23c and 230., which has a substanilly circular cross section, is disposed so that the axis thereof, if ex ended downwardly into chamber 15, would pass through a p int located substantially at the intersection of the inner wall surface of the shell 11 and the inner surface of the chamber floor 12, as Fig. 1 shows. Cover member 13 is also provided with four orifices 24a, 24b, 24c and 24d which extend therethrough and which communciatss with chamber 15 and which are arranged with respect to each other as shown in Fig. 2.

The invention operates in the following manner:

Assume that inlet pipe 22 and outlet pipe 25 are con nected to device 10 as shown in Fig. 3 and that the device is in the substantially upright position shown therein."

Further assume that a suitable liquid coolant is being forced or pumped under pressure, which, for example should be greater than eight p unds per squa e ll'l'h, 1 through pipe 22 from a source (not shown) tow"rd de-' vice 10. The coolant entering recess 21 is forced thrrugh the orifices 23a, 23b, 23c and 23a and is thus b oken into four soid jet streams of relatively high vel city Each of the four streams is aimed toward the juncion of the inner surfaces of the side and bottom wall 12 of shell 11. As each solid stream impinges against the in-.

terior surface of the shell 11 at the said junct'on po nt, it loses its character as a solid stream and is forced to swirl back upon itself. Some of the coolant swir's up the side wall of shell 11 for a short distance and some is a I forced across the bottom wall 12. This localized tu 'bumass.

-Patented Jan. 10, 196-1;

nozzle 25 from whence it can be directed as desired.

Preferably, the rate at which coolant is introduced into .device should be such that moat 16 is filled to overflowing with coolant in the foamy state. However, shou'd coolant be introduced too rapidly with respect to the capacity of moat 16 or the capacity of opening 17 to carry it away, the moat tends to fill with coolant in its liquid state and the foaming action is defeated.

The orifices 24a, 24b, 24c and 24d in cover 13 permit the ingress and egress of air into chamber while foam is being generated and should be sufiiciently large to prevent reduction of air pressurepf formation of a partial vacuum within chamber 14 as coolant fiows through device 10 which would tend to inhibit or interfere with the smooth and constant flow of foam from opening 17. Reduced air pressure within chamber 15 tends to cause air to be drawn up through discharge opening 17.

It will be apparent to those skil ed in the art that although device 10 has been shown as comprised of the shell member 11 and the cover member 13, the device could be manufactured as an integral unit.

I claim:

1. In combination, a hollow cylindrical member, a top portion enclosing the top end of said member, said top portion being adapted for connection to the discharge end of a tube supplying liquid under pressure, said top portion being provided with a plurality of angularly disposed apertures for directing said fluid into said hollow cylindrical member and toward the side and bottom thereof in jet streams, means comprising at least one aperture for permitting egress and ingress of air into said hollow cylindrical member, a bottom port'on enclosing the bottom end of said member, said bottom portion being provided with a centrally disposed aperture, and a projection surrounding said centrally disposed aperture inside of said cylindrical member to provide a moat between said centrally disposed aperture and the side of said cylindrical member, said moat being adapted to retain a quantity of liquid therein, whereby said jet streams play upon said liquid in said moat to break it into foam, said to m being momentarily contained in said moat before spilling over into the said centrally disposed aperture.

2. A device for generating foam comprising an enclosed chamber having side and bottom walls, at least one air port communicating with the upper portion of said chamber, for the ingress and egress of air, at least one opening through said bottom wall of said chamber, means disposed about said opening to form a moat between said opening and said side wall, said moat being adapted to retain a substantial quantity of liquid before said liquid reaches the top level of said means, and means associated with the upper portion of said chamber and adapted for connection with the discharge end of a tube containing liquid under pressure to form said liquid into jet streams of relatively high velocity, said last recited means comprising a member provided with a plurality of holes of relatively small diameter adapted to direct said streams toward a line formed by the intersection of the inner surfaces of said side and bottom walls of said container.

References Cited in the file of this patent UNITED STATES PATENTS 1,519,312 Kelleher Dec. 16, 1924 2,210,846 Aghnides Aug. 6, 1940 2,386,918 Timpson Oct. 16, 1945 2,447,123 Jones Aug. 17, 1948 FOREIGN PATENTS 365,513 Great Britain Jan. 11, 1932 

